Metamaterial, and method and apparatus for adjusting frequency of metamaterial

Abstract

The present invention discloses a metamaterial, and a method and an apparatus for adjusting a frequency of the metamaterial. The metamaterial includes a substrate material, and an electrically controllable microstructure unit array disposed on the substrate material and including a plurality of electrically controllable microstructure units. Each electrically controllable microstructure unit includes an external metal structure, an internal metal structure, and a varactor diode. The internal metal structure and the external metal structure define a ring-shaped channel. The varactor diode is disposed in the ring-shaped channel of each electrically controllable microstructure unit, and is configured for adjusting an operating frequency of each electrically controllable microstructure unit according to a voltage applied across the varactor diode. According to the present invention, a technical problem of failing to quickly and accurately adjust an operating frequency of the metamaterial in the prior art is solved.

What is claimed is: 
     
       1. A metamaterial, comprising:
 a substrate material; and 
 an electrically controllable microstructure unit array attached on the substrate material and comprising a plurality of electrically controllable microstructure units; wherein each electrically controllable microstructure unit comprises: 
 an external metal structure; 
 an internal metal structure; wherein the internal metal structure and the external metal structure define a ring-shaped channel; and 
 a varactor diode disposed in the ring-shaped channel of each electrically controllable microstructure unit; wherein the varactor diode is configured for adjusting an operating frequency of each electrically controllable microstructure unit according to a voltage applied across the varactor diode; 
 wherein the voltage applied across the varactor diode is a variable reverse bias direct current voltage. 
 
     
     
       2. The metamaterial of  claim 1 , wherein the external metal structure is a rectangular structure or a square structure, the internal metal structure is a rectangular metal patch, and the internal metal structure is nested in the external metal structure. 
     
     
       3. The metamaterial of  claim 1 , wherein an adjustment range of the operating frequency is 0.3 GHz to 300 GHz. 
     
     
       4. The metamaterial of  claim 1 , wherein the voltage applied across the varactor diode is from 0V to 20V. 
     
     
       5. The metamaterial of  claim 1 , wherein a direction from a positive electrode to a negative electrode of the varactor diode or a direction from the negative electrode to the positive electrode of the varactor diode in the ring-shaped channel is the same as a direction of an electromagnetic field in the metamaterial. 
     
     
       6. The metamaterial of  claim 1 , wherein the substrate material is a nonmagnetic medium material, a permittivity of the substrate material is from 2 to 10, and a permeability of the substrate material is equal to 1. 
     
     
       7. The metamaterial of  claim 1 , wherein the dimensions of any two electrically controllable microstructure units in the electrically controllable microstructure unit array are the same. 
     
     
       8. The metamaterial of  claim 1 , wherein the metamaterial further comprises:
 a coaxial through hole disposed in the internal metal structure; wherein the internal metal structure is connected to a feed network through the coaxial through hole, and is configured for applying the voltage across the varactor diode. 
 
     
     
       9. The metamaterial of  claim 1 , wherein an electromagnetic wave perpendicularly incident to surfaces of the external metal structure and the internal metal structure is a plane wave, an amplitude and a phase of the electromagnetic wave are the same in a direction that is perpendicular to the incident direction. 
     
     
       10. The metamaterial of  claim 1 , wherein in a predetermined frequency band, a distance between any two adjacent electrically controllable microstructure units in the electrically controllable microstructure unit array is equal to a predetermined distance, the predetermined distance is from ½λ to λ, and λ is a wavelength of an electromagnetic wave in the metamaterial. 
     
     
       11. The metamaterial of  claim 1 , wherein the varactor diode is specifically configured for reducing an operating frequency band of the metamaterial if a capacitance of the varactor diode is increased; or
 the varactor diode is specifically configured for increasing an operating frequency band of the metamaterial if a capacitance of the varactor diode is reduced; wherein the capacitance of the varactor diode is adjusted by adjusting the voltage applied across the varactor diode. 
 
     
     
       12. A method for adjusting a frequency of a metamaterial, the metamaterial comprising a substrate material and an electrically controllable microstructure unit array that is attached on the substrate material and comprises a plurality of electrically controllable microstructure units, each electrically controllable microstructure unit comprising an external metal structure, an internal metal structure, and a varactor diode; the internal metal structure and the external metal structure defining a ring-shaped channel, the varactor diode disposed in the ring-shaped channel of each electrically controllable microstructure unit; wherein the method comprises:
 step 1: obtaining a voltage applied across the varactor diode, wherein the voltage applied across the varactor diode is a variable reverse bias direct current voltage; 
 step 2: determining whether an operating frequency of the metamaterial satisfies a predetermined frequency; and 
 step 3: adjusting the voltage across the varactor diode if it is determined that the operating frequency of the metamaterial does not satisfy the predetermined frequency, so as to make the operating frequency of the metamaterial satisfy the predetermined frequency; wherein the operating frequency of the metamaterial changes as the voltage across the varactor diode changes. 
 
     
     
       13. The method of  claim 12 , wherein the step 2 comprises:
 determining whether the operating frequency of the metamaterial is greater than or equal to the predetermined frequency; and 
 wherein the step 3 comprises: 
 reducing the voltage applied across the varactor diode if it is determined that the operating frequency of the metamaterial is greater than or equal to the predetermined frequency; or 
 increasing the voltage applied across the varactor diode if it is determined that the operating frequency of the metamaterial is smaller than the predetermined frequency. 
 
     
     
       14. The method of  claim 12 , wherein the step 3 comprises:
 reducing an operating frequency band of the metamaterial if a capacitance of the varactor diode is increased; or 
 increasing an operating frequency band of the metamaterial if a capacitance of the varactor diode is reduced; wherein the capacitance of the varactor diode is adjusted by adjusting the voltage applied across the varactor diode. 
 
     
     
       15. An apparatus for adjusting a frequency of a metamaterial, the metamaterial comprising a substrate material and an electrically controllable microstructure unit array that is attached on the substrate material and comprises a plurality of electrically controllable microstructure units, each electrically controllable microstructure unit comprising an external metal structure, an internal metal structure, and a varactor diode; the internal metal structure and the external metal structure defining a ring-shaped channel, the varactor diode disposed in the ring-shaped channel of each electrically controllable microstructure unit; wherein the apparatus comprises:
 an obtaining unit, configured for obtaining a voltage applied across the varactor diode, wherein the voltage applied across the varactor diode is a variable reverse bias direct current voltage; 
 a determining unit, configured for determining whether an operating frequency of the metamaterial satisfies a predetermined frequency; and 
 an adjustment unit, configured for adjusting the voltage across the varactor diode if it is determined that the operating frequency of the metamaterial does not satisfy the predetermined frequency, so as to make the operating frequency of the metamaterial satisfy the predetermined frequency; wherein the operating frequency of the metamaterial changes as the voltage across the varactor diode changes. 
 
     
     
       16. The apparatus of  claim 15 , wherein the adjustment unit comprises:
 a determining module, configured for determining whether the operating frequency of the metamaterial is greater than or equal to the predetermined frequency; 
 a first control module, configured for reducing the voltage applied across the varactor diode if it is determined that the operating frequency of the metamaterial is greater than or equal to the predetermined frequency; and 
 a second control module, configured for increasing the voltage applied across the varactor diode if it is determined that the operating frequency of the metamaterial is smaller than the predetermined frequency. 
 
     
     
       17. The apparatus of  claim 15 , wherein the adjustment unit is specifically configured for reducing an operating frequency band of the metamaterial if a capacitance of the varactor diode is increased; or
 the adjustment unit is specifically configured for increasing an operating frequency band of the metamaterial if a capacitance of the varactor diode is reduced; 
 wherein the capacitance of the varactor diode is adjusted by adjusting the voltage applied across the varactor diode. 
 
     
     
       18. The apparatus of  claim 15 , wherein the external metal structure is a rectangular structure or a square structure, the internal metal structure is a rectangular metal patch, and the internal metal structure is nested in the external metal structure. 
     
     
       19. The apparatus of  claim 15 , wherein the dimensions of any two electrically controllable microstructure units in the electrically controllable microstructure unit array are the same. 
     
     
       20. The apparatus of  claim 15 , wherein the metamaterial further comprises:
 a coaxial through hole, disposed in the internal metal structure; wherein the internal metal structure is connected to a feed network through the coaxial through hole, and is configured for applying the voltage across the varactor diode.